Abstract:
Rapid gravity granular media filters are widely used in the water and wastewater treatment industries. Regular backwashing to clean the filters is a vital part of their efficient operation.
In the present study, emphasis was given on the removal of fine suspension particle by filtration through low cost coarse media. A set up was made in the laboratory and filtration process was proceeded. The media taken was the mixed bed of Calcite-Anthracite, Calcite-Garnet & Anthracite-Garnet. Clay was added in a definite amount (20 mg l-1) in tap water and this suspension was used. Samples at regular intervals were collected and analyzed. Also, the effect of pressure drop was taken into consideration.
Results obtained indicated_that the removal efficiency was best observed in the case of "Calcite-Garnet" as compared to "Anthracite-Garnet" and "Calcite-Anthracite"
mixed beds. At 500 mm bed height, at a flow rate of 30 dm3 the removal efficiency of Calcite-Garnet was found to be 99.99%, of Anthracite-Garnet it was 99.85 % and of Calcite-Anthracite it was found 99.5% at time interval of 60 min. Studies on the effect of different parameter on the removal performance of fine suspended particle shows that a smaller particle size, a greater filter depth, shorter cycle time gave an advantage in removal efficiency.
